JPH05273000A - Abnormality monitoring device - Google Patents

Abstract

PURPOSE:To obtain an abnormality monitoring device which can judge abnormality properly even for a process which repeats fluctuation of state at a certain period. CONSTITUTION:A normal allowable range is determined as a time function for one-period fluctuation of a physical quantity which is related to the state of a process. By operating a process device, the physical quantity which actually fluctuates is compared with a previously determined allowable range. When the actual physical quantity reaches outside the allowable range (a shadow part A5, a shadow part B6, a shadow part C7), it is judged that an abnormality has occurred. The allowable range of a normal state can be specified flexibly along time instead of a fixed value. Therefore, even if a process state repeats a large fluctuation periodically, a normal abnormality judgment can be made constantly by comparison with the allowable range.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an abnormality monitoring device for monitoring whether a process device such as a magnetic disk manufacturing device or a semiconductor manufacturing device is abnormal.

[0002]

2. Description of the Related Art It is desirable to be able to promptly deal with the occurrence of any abnormality in a process device and prevent the influence from expanding. For that purpose, an abnormality monitoring device capable of appropriately determining whether the process state is normal or abnormal is required. Conventionally, a process abnormality monitoring device is disclosed in JP-A-61-161.
As in the invention described in the publication No. 16307, a threshold value within an allowable range is set for the value of the physical quantity related to the process state, and it is determined that the case where the value of the physical quantity exceeds the threshold value is abnormal.

[0003]

The above-mentioned conventional technique cannot cope with the case where the process state is repeatedly changed in a constant cycle and the physical quantity related to the state is also greatly changed in the constant cycle. If the set permissible range is narrow, even in a normal state, the periodic fluctuation of the physical quantity related to the process state exceeds the threshold value, and it is determined to be abnormal, and correct determination cannot be performed. On the contrary, if the set allowable range is wide, the normal state as described above is not determined to be abnormal, but the threshold value is not exceeded even if the variation should be determined to be abnormal, and it is determined to be normal. After all, the correct judgment cannot be made. An object of the present invention is to provide an anomaly monitoring device that can correctly make an anomaly judgment even when the state of a process fluctuates greatly periodically.

[0004]

In order to achieve the above object, a normal permissible range is determined as a time function with respect to a variation of each physical quantity for one cycle. The physical quantity that actually changes over time by the operation of the process device is compared with a predetermined allowable range. If the actual physical quantity is outside the allowable range, it is determined that an abnormality has occurred.

[0005]

[Function] The allowable range of the normal state can be flexibly designated along the time, instead of being a constant value. Therefore, even if the state of the process fluctuates greatly periodically, with the progress of time,
The allowable range of the normal state can be changed according to the fluctuation of the process state. By comparing this allowable range with the actual physical quantity moment by moment, it is possible to always make a correct abnormality determination.

[0006]

An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a block diagram of an abnormality monitoring device of the present invention and a process device to be monitored. FIG. 2 shows the outline of the operation of the abnormality monitoring device of the present invention. As the process device 1 operates, the state of the process changes. Along with this change, various physical quantities related to the process state change. The abnormality monitoring device 2 of the present invention collects the values of various physical quantities as process data by sampling 3 and analyzes them by abnormality judgment 4 to determine whether or not an abnormality has occurred. FIG. 3 shows an example of fluctuation of a certain physical quantity related to the state of the process. The horizontal axis shows the time t when the process start time is 0, and the vertical axis shows the value x of a certain physical quantity. A thick line shows an ideal fluctuation waveform, and a thin line shows an example of an actual fluctuation waveform. The abnormality monitoring device 2 samples the actual variation value at a predetermined time point and uses it as the process data. White circles are sampled process data. The abnormality monitoring device 2 compares the process data with the ideal variation and determines whether or not an abnormality has occurred depending on the degree of the difference. For the abnormality determination, reference values x _r , t _s , t _e , a, b, and
c and d are provided.

(1) The target ideal value is x _r , the allowable range is ± a%, and the allowable overshoot amount is + b%.

(2) Let t _{s be} the time of the start end that must fall within the allowable range of (1), and let the allowable range be + c%.

(3) The end time that must be within the allowable range of (1) is t _e , and the allowable range is -d%.
And

A procedure for determining an abnormality will be described. The determination method is divided as follows according to the time t.

[0011]

[Equation 1] (1) When 0 ≦ t <((100 + c) / 100) t _s When the value of the process data is larger than ((100 + b) / 100) × _r , that is, the shaded area A5 in FIG. 3 is entered. In this case, the allowable overshoot amount is exceeded and it is determined that an abnormality has occurred.

[0012]

[Equation 2] (2) ((100 + c) / 100) t _s ≤ t ≤ ((100
-D) / 100) the value is ((100 + a process data when t _e) / 100) is greater than x _r, that is, when it enters the hatched portion B6 of FIG. 3, it is assumed that there is a steady-state error or vibration unacceptable , It is determined that an abnormality has occurred.

The value of the process data is ((100-a) / 10
If it is smaller than 0) x _r , that is, if it enters the shaded area C7 in FIG. 3, it is determined that an unacceptable steady-state deviation, vibration, or response is slow, and an abnormality has occurred.

[0014]

EFFECT OF THE INVENTION The allowable range of the normal state can be flexibly designated along the time, instead of being a constant value. Therefore, even when the state of the process repeats large fluctuations periodically, by comparison with the allowable range of the normal state set along the time,
A correct abnormality determination can always be made.

[Brief description of drawings]

FIG. 1 is a block diagram of an abnormality monitoring device of the present invention and a process device to be monitored.

FIG. 2 is an operation schematic diagram of the abnormality monitoring device of the present invention.

FIG. 3 is a diagram showing an example of a change in a certain physical quantity related to a process state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Process apparatus, 2 ... Abnormality monitoring apparatus, 3 ... Sampling, 4 ... Abnormality judgment, 5 ... Shaded area A, 6 ... Shaded area B, 7 ... Shaded area C.

Claims (4)

[Claims] 1. A process apparatus in which a process is repeated at a constant cycle, a value serving as a criterion for abnormality is provided as a time function for one cycle with respect to a physical quantity related to a periodical state change, and an actual value of the physical quantity is set. An abnormality monitoring device, which collects time-series data from a process device and determines whether or not an abnormality has occurred by comparing a reference value with an actual value. 2. In a process device in which processing is repeated at a fixed cycle, a value serving as a criterion for abnormality is provided for one cycle as a function of time with respect to a physical quantity related to a periodical state change, and an actual value of the physical quantity is set. An abnormality monitoring method characterized in that the presence or absence of an abnormality is determined by collecting data from process devices in time series and comparing a reference value with an actual value. 3. In a process device in which processing is repeated in a fixed cycle, an ideal value of fluctuation is provided as a function of time for one cycle with respect to a physical quantity related to periodical state changes, and an actual value of the physical quantity is set in the process device. Collected in chronological order from
An abnormality monitoring device characterized by determining the presence or absence of an abnormality by comparing an ideal variation value and an actual value. 4. An abnormality processing device comprising a processing unit for performing appropriate processing for an abnormality detected by using the abnormality monitoring device according to claim 1.